This enclosure is designed to work with an activated carbon air filter plus an exhaust vent with activated carbon and a nanoparticulate filter (better than HEPA). Put a thermometer inside the build chamber and adjust the amount of activated carbon filtration media to adjust the temperature inside the build chamber. The more filtration media, the less exhaust airflow, the higher the temperature. For ABS prints that don't crack, curl, nor warp, the temperature inside the build chamber should be 100 to 120 degrees Fahrenheit. A free downloadable 3d printed activated carbon air filter plus an exhaust vent with activated carbon and a nanoparticulate filter are available from http://www.3dprintfilemarket.com . Unlike other designs that use expensive cartridges that cost $40 per month to operate, this design uses affordable activated carbon granules and surgical masks that cost only pennies per month of operation. Other enclosure designs also require expensive laser cutters. This design is entirely 3d printed and doesn't require any laser cutting. Enjoy!

Instructions

Note: each numbered block of instructions match with a numbered illustration in the images section.

1. Go to the hardware store and have them cut some 2 mm acrylic panels for you; Qty 2 x 200 mm x 320 mm for front and back of hood, Qty 2 x 200 mm x 328 mm for sides of hood, Qty 1 x 320 mm x 328 mm for top of hood, and Qty 1 x 316 mm x 320 mm for the removable front window. On the back of hood 2 mm acrylic panel, on the bottom of the panel, measure 50 mm from the left edge and cut a 40 mm wide x 80 mm tall hole through the panel. On this same panel, on the top of the panel, measure 80 mm from the left edge and 15 mm from the top edge for the position of the 40 mm fan. Mark 4 points that are the corners of a square that is 32 mm on each side. Using a 7/64 inch drill bit, drill out the 4 marked points. In the center of these 4 holes, use a compass to draw a circle with a 25 mm diameter. Using your smallest drill bit, drill all along the circumference. Then, using a small electric saw or a very sharp hobby knife, cut out this 25 mm diameter hole.  
 
2. Hold 2 acrylic panels and a corner fastener together and mark all the points to drill on the acrylic panels in order to match with the corner fasteners. Do this for all the panels and corner fasteners. Use a 1/4 inch drill bit to drill everywhere that you've marked. Use a needdle nose plier and an adjustable wrench to bolt all the acrylic panels to the corner fasteners. Seal the edges with silicone caulk.  
 
3. Attach panel hangers and panel clip to your Ultimaker.  
 
4. On top of removable front window panel, mark a point 15 mm from the top and 15 mm from the left. Mark another point 15 mm from the top and 15 mm from the right. Use a 1/4 inch drill bit to drill through these marks. Screw in 2 bolts into these holes but do not allow the bolt ends to go all the way through and protrude from the panel.  
 
5. Slip the removable front window panel into the bottom panel clip on your Ultimaker. Mark where you would have to drill in order for the panel to hang on the two panel hangers attached to your Ultimaker. Use a 5/16 inch drill bit to drill through these marks. At least 6 mm below these holes, use a compass to draw a 22 mm diameter circle. Using your smallest drill bit, drill many holes all along the circumference of this circle. Use a hobby knife or saw to cut out this circle. Cut an 8 mm wide channel from the top of this circle to the 5/16 inch hole you drilled right above this circle.   
 
HINTS; If the bolts are too tight, oil them with vegetable oil before screwing them in. If the panel hangers and panel clips don't fit, soften them with a heat gun and make them fit. These pieces are a tight fit on purpose. If the pieces are looser, then they will shake apart while the Ultimaker is printing.
 
If the removable front panel window doesn't fit on the panel hangers, do not use a bigger drill bit. Doing so will cause the panel to rattle while the Ultimaker is printing. Just insert your 5/16 inch drill bit and wiggle it around while drilling for a minute or two. This will loosen it enough to fit, but not too loose so that it rattles.  
 
Print these pieces in ABS. To prevent cracking, warping and curling while printing these pieces before you've built your enclosure, create a temporary enclosure with plastic wrap and electrical tape.  
 
All pieces are printed without supports exept for UltimakerCase3.stl . Print UltimakerCase3.stl with supports. Remove support structures with a needle nose plier before use.

Update 6/27/14
The hood on top of the Ultimaker was a bit wobbly, so I added reinforcements to the seams between the front and back pieces with the side pieces of the hood. The updated build plate is UM2FullPlateA2.stl . Be sure to glue these reinforcements to the acrylic plates.